Diesel engine fuel system



W. E. GREENE DIESEL ENGINE FUEL SYSTEM Filed Feb. 20, 1957 3 Sheets-Sheet 1 Feb. 7, 1939.

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Feb. 7, 1939. w GR ENE 2,146,139

DIESEL ENGINE FUEL SYSTEM Filed Feb. 20, 1937 3 Sheets-Sheet 3 w. E. Greene any 42/1 Patented Feb. 7, 1939 UNITED STATES,

PATENT OFFICE DIESEL ENGINE FUEL SYSTEM Whitney Eastman Greene, El Paso, Tex. Application February 20, 1937, Serial No. 126,929 2 Claims. (Cl. 123-33) The objects of my invention are:

First, to deliver and distribute the fuel supply from a single fuel pump to the various cylinders of a multi-cylinder engine in such a manner that each cylinder will receive a uniformly equal supply of fuel at exactly regulated intervals, with accurate control of this distribution for varying speeds and loads;

Second, to prepare the fuel before entering each cylinder so that each particle is made more ready for combustion than by any other method, and in such complete distribution-throughout the air in the combustion chamber so that a greater thermal eificiency will be obtained;

Third, to make it possible to deliver the fuel to each cylinder in such a manner that, very little pressure in the fuel delivery system is required,

thereby making possible higher speed engines at lower costs;

Fourth, to make possible a cooler running engine, with a minimum of so cal1ed after-buming, and a uniform and complete combustion;

Fifth, to provide a novel combination and arrangement of parts in the several forms of the invention disclosed in the accompanying drawings and hereinafter described.

I I attain these and other objects of my invention by the mechanism illustrated in the accompanying drawings, in which- Figure 1 is a side elevation of my invention applied to a six-cylinder, internal combustion engine of the Diesel type with a portion of one of the cylinders shown in vertical section;

Fig. 2 is a vertical section through the cylinder head and a portion of the cylinder and piston of a Diesel engine on line 22 of Fig. 3 illustrating the combined pump and injection nozzle for diffusing the charge;

Fig.- 3 is a horizontal section on line 3-3 of Fig. 2, showing just where and how the fuel is introduced to the air during the compression stroke;

Fig. 4'is a vertical section of a modified form of combined pump and injection nozzle which I have devised;

Fig. 5 is a horizontal section on line 4-4 of:

Fig. 4, and;

Fig.6 is a vertical section of another form of manner of such chamber I provide a novel fuel dissupplied through conduit 3. The fuel is supplied through conduits 8 to the cylinder head l3, as illustrated in Figs. 2 and 3. Distributing valve 5 is rotated by shaft 4, driven from some suitable source of power as by a gear and chain connection 5 with a gear on the cam shaft C, as indicated in dotted lines in Fig. 1. As shown in Fig. 4 a suitable packing nut 9 is threaded on the end of valve casing 2.

Referring to Figs. 2 and 3 there is illustrated a cylinder ll, piston i2 and cylinder head l3 of my improved form of Diesel engine, showing the manner in which fuel is delivered to the combustion chamber. Mounted in the cylinder head i3 is a combinedpump and injection nozzle M for diffusing the charge which has a plunger I 5 actuated from the cam shaft K to compress air and fuel in the compression chamber l6. Fuel is supplied through conduit 8 to diverging channels 20 and thence to the radiating channels l8 and thence to orifices I9 into the top of the com-- bustion chamber 2|, as shown in Figs. 2 and 3. The orifices l9 may be fitted with plugs which are threaded and have openings of any suitable size and shape desired, preferably shaped to cause fuel to spread as much as possible such as plugs 3| 'shown'in Fig. 11.- Multiple passages I8. are preferred, but I may provide a single passage [8 from conduit 8, and a single orifice l9 for'eacl'i of the several formsof my invention. 30

As shown in Fig. 3, the fuel which enters through conduit 8 passes through channel 20 into the passages I 8 at an acute angle, preferably but not necessarily. The several channels l8 connect all the orifices l9 and also the small chamber l6, (shown in Fig.2) under the usual spray plunger. Plunger l5 operates in the usual plungers, being forced inwardly bya cam and rocker mechanism so as to displace the contents of chamber l6 and then return outwardly by force of a spring at its head when the camon the cam shaft releases. In operation the system of .fuel supply isas follows: Assuming the engine is a four-cycle one, piston. 52 moves outwardly on a suction stroke drawing in a charge of fresh air through intake 22, and on the pistons return stroke, this air begins to compress. Chamber 23 is the exhaust. As compression pressure increases, plunger l5 starts to move upward due to spring action and cam release (orhas already moved outward) leaving I 6. The increase of compression pressure in combustionchamber 2| forces air through all the openings I 9 so that the pressure in passages l8 and chamber l6 increases as piston 55 moves toward cylinder head I3. Before this pressure is very appreciable and while air is rushing through passages I8 by the points 28a at a very high rate, the fuel is timed to enter through conduits 8, (as previously described), thence through passages 28 at points 28a. Because of the acute angle, very little pressure will be required in the fuel system.

By the time the piston has reached the inner end of its stroke and pressure in combustion chamber 2|, channels I8 and chamber I6 are at their maximum, the plunger I5 starts to move inwardly due to cam action. This is so timed that contents of chamber I6 (fuel and air) are forced out through all the orifices I9, and combustion takes place in a steady, positive and complete manner. After this power stroke and the return exhaust stroke, the cycle repeats.

The usual practice in delivering the fuel charge into the cylinder is to have the injection or spray nozzle, as it is sometimes called, as close to the combustion chamber as possible, so that the inward stroke of plunger I5 will completely dis- 7 charge all fuel from compression chamber I6 into combustion chamber 2|. At first glance and from a theoretical standpoint this seems desirable. My design very evidently does not do this, and apparently is at a disadvantage in that injection of fuel leaves quite a supply left over in passages I8. This, however, is a great advantage and is a primary part of the invention. The chief advantage lies in the fact that sufiicient fuel (though a very small part of each charge) remains in these passages I8 to mix with the air on compression stroke as this air rushes through these passages I8, through orifices I9. This mixture of fuel and air becomes effective when piston nears it inner end of stroke and pressures have risen to over 400 pounds per square inch, for the fuel therein will ignite at this high pressure (due to great rise in temperature of air) and in igniting will heat the new charge of fuel much more than would otherwise be the case. This new charge of, fuel, having come into passages I8 at 28a from conduit 8 'and passages 28 is in a much different physical state than is the case reaches point 28a it is snatched away and completely vaporized-by th-epowerful rush of compressed air past point 28a through passages I 8.

This method of shattering the fuel at'point 28a Ibers 48 and 4| and spacing the upper end of and combining it with some hot fuel left over after each power stroke, and the delivery of each fuelcharge through several orifices I9 gives a much improved preparation of the fuel charge.

Another important advantage from the standpoint of cost and maintenance of the fuel system lies in the feature of making it possible to deliver the fuel supply at point 2811 at very little above atmospheric pressure, although from resistance in pipe lines and fuel distributor valve,

ing the conventional combined pump and fuel in- I jection single plunger I5 shown in Fig. 2. The

inner plunger 48 is slidably mounted in the outer and upper plunger 4| with a spring 42, seated in a recess in member 4| interposed between memmember 48 from the upper end of chamber 43 of upper plunger member 4|, to normally maintain the space or chamber 43 between these plunger elements. Inner plunger member 48 has opposite similar channels 45 extending from its upper end to a point about half way down that member and opening intochambers 41. Channels 48 are provided in the plunger casing 58, extending from a point adjacent the lower end 46 of upper outer plunger member 4| to the combustion chamber 2|. A suitable key 49 carried by plunger 48 and traveling in 2. corresponding recess in plunger 4| prevents plunger 48 from separating from plunger 4|. The recess may be made annular if desired.

As the piston comes to the end of its comnels -48 to annular chambers 41 .and thence through channels 45 to chamber 43 and these spaces, like the combustion chambers, will be filled with compressed air to 500 pounds to-the square inch. When injection of fuel starts, the cam operating the plunger 4| will force that plunger inwardly so that the lower end 46 of plunger. immediately covers the upper end of channels 48 where they open into the annular chamber 41. This operation traps all the air in chamber 41 and chamber 43 so that plunger 48 not only displaces all the fuel and air in chambers I6, as previously described, but the continuous motion of .plungers 4| and 48 will operate to expel all the air in chambers 41 and 43 out through the channel 44 extending longitudinally through the center of plunger 48. In other words all the air in chamber 41 will be forced out through passages 45 into chamber 43, and thence down through channel 44 and out through passage I1 into channels I8 and thence through orifices I8 into the combustion chamber. This design especially for large engines would be advantageous in mixing the fuel and air and thoroughly completing combustion.

The reason that channels 48 are so important is due to the fact that chambers 41 and 43 are filled with air at 508 pounds pressure at the start, and this means that something happens immediately on the start of the inward movement of plunger 4| .-If, however, these spaces were filled with atmospheric air, little or no benefit would result. Return of plunger 4| outward then opens 48 so that the next compression stroke will complete the cycle described.

In Fig. 6 there is illustrated a simplified application ofpthe formof invention illustrated in I4 and I5. In Fig. 6 there are provided one or more conduits 55- leading from combustion cham- "ber 2| to annular chamber 41 around lower end of plunger I5 for the passage of air to chamber 41 from combustion chamber 2|. A passage 51 extends transversely through plunger I5, whereby on downward movement of plunger I5, the air compressed in annular chamber 41 may flow through passage 51. as indicated by the arrows, into fuel the same pressure is transmitted through chanchamber I6, which is in communicationthrough passage I1 with the fuel channel I8 and with nozzle opening I8 into the internal combustion chamber. In this form of the invention the plunger I5 with its reduced and channeled lower It will be observed that a characteristicand'" -novel feature of my invention is that the fuel is delivered not at a hot point calculated to make carbon, but in a chamber or at a point which is well away from the hot center and well cooled by circulating water, yet the fuel is completely shattered and vaporized mechanically by forcing air into and mingling it with the fuel, and then heating the mixture in a suitable chamber by compression after it has been mechanically vaporized. In this way I avoid any possibility of carbon forming and have improved over the-prior art.

I What I claim is:

1. In an oil engine of the type described, the combination of a cylinder and piston movable therein-, a cylinder head, fuel supply conduits in the cylinder head, a series of radiating conduits with which the fuel supply conduits communicate, nozzles opening out of said radiating conduits into the combustion chamber of the engine, an outer plunger, an inner plunger slidably mounted in the outer plunger, a spring interposed between said plungers, means for mechanically actuating said outer plunger at predetermined intervals relative to the operation of the pistons, a chamber adjacent said inner plunger, an air conduit opening out of the combustion chamber and extending to the aforesaid chamber adjacent the inner plunger, a fuel compression chamber on the under side of the inner plunger, an air passage through the inner plunger to the upper end thereof, and a separate air passage through the inner plunger extending from the upper end thereof to the air compression chamber at the lower end thereof.

2. In an oil engine of the type described, the combination of a cylinder and piston. operable therein, a cylinder head, a plunger casing mounted in the cylinder head, an outer plunger reciprocably operable in said casing, a second plunger slidably mounted below said outer plunger, a compressible element normally spacing the upper end of the second plunger from the outer plunger, the space thus formed constituting an air compression chamber, a fuel compression chamber at the lower end of the second plunger, a channel communicating between the air compression chamber above and the fuel compression chamber below the second plunger, fuel passages radiating through the cylinder head, orifices from said passages into the combustion chamber, and a passage from the fuel compression chamber communicating with said fuel passages and with the combustion chamber, said fuel compression chamber being spaced substantially from the combustion chamber.

WHITNEY EASTMAN GREENE. 

